Phonograph



Nw. 25, m21.

A. W. HOOVER ET AL PHONOGRAPH Filed Nov. 12. 1919 PIII 2- '.--Vff 9 WITNESS 7 v Wfffw- Patented Nov. 25, 1924.

aerea armar AUSTIN W. HOOVER AND ROBERT WINTER, JR., F IRWIN, PENNSYLVANIA, AS-

SIGNO'R-S TO DUAL-TONE PHONOGRAPH & MANUFACTURING COMPANY, OF TITANOR BOROUGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

PHONOGRAPH.

Application :tiled November 12, 1919. Serial No. 337,605.

To @ZZ whom t may concern:

Be it known that we, AUSTIN W. Hoovnn and ROBERT VINTER, J r., citizens of the United States, and residents of Irwin, in the county of Vcst-moreland and State of Pennsylvania, have made a new and useful Improvement in Phonographs, of which the following is a specication.

Our invention relates to sound reproducing devices and consists of phonograph parts adapted to develop and deliver sound waves from the usual sound records more eiciently and with better tonal results than similar parts previously used.

One of the defects of present phonographs is their inability to reproduce all of the sounds recorded and their faulty reproduction and amplification of the tones of the sounds which they do yield. The object ot our invention is to eliminate these defects and we attain our `object by manufacturing phonograph reproducing and developing parts of a material hitherto unused for that purpose and by providing otherwise improved passages thru vvhich the sound waves travel to the atmosphere.

In the accompaning drawings, Figure 1 is a partial section and elevation of the main parts of a phonograph; Fig. 2 is a plan and section oit the same parts and Fig. 3 is a vertical section on line 3 3 of Fig. 1.

Partition 1 of the phonograph box or cabinet supports the rotating table 2 for record 3 and supports a collar 4 for base of the tone arm. The entrance end of the sound chamber 6 is also secured topartition 1 and alined with the end of collar 4 and tone arm base 5. A sound boX 7 is mounted on the vertically pivoted end 8 of the tone arm and is provided with a needle 9 ot the usual type.

The tone arm begins with the usual tubular passage as indicated at 8 but a short distance from the sound box 7 the passage di vides and forms two passages 10 and 11, r which diverge irom each other and are pivotally telescoped into passages 12 and 13 respectively, which form continuations of pas sages 10 and 11, expand thruout their length and, at the rear of the arm, unit-e in base 5 50 opening into sound chamber 6.

Each sound wave created at the sound box travels thru passage 8 and, at the divisional point, generates duplicate waves which travel thru both passages 10-12 and 11-13 and at the end of these passages unite in a single wave to proceed thru base 5 and collar 4 to sound chamber 6. The end of basc- 5 telescopes into collar 4 and is supported. upon ball bearings 14 and is secured against unintentional removal from its seat by a screw 15 attached to a bridge 16'in collar 4. This support gives the divided arm pivotal movement about the axis of its base.

The use of a double tone arm gives remarlrable results in the tonal qualities of the sounds reproduced. By substituting our arm for a single arm we have obtained from the same record and with the same sound box, not only better tones for all sounds. but even some sounds not previously audible.

While we have illustrated a tone arm having but two separate passages it will be ap-v parent that the arm may be divided into any number ot passages and fall within the spirit of this invention.

Those parts of sound boX 7 which are usually made of brass or other metal.l we construct of a phenolic condensation product. some 'familiar examples ot which are marketed under the trade names bakelite, rodmanolf condensite, etc, The tone arm is preferably made ot' the same substance altho. even when constructed of wood or such metals as are utilized in the ordinary tone arms, the greatly improved results men* tioned are obtained.

The tone chamber 6 is also formed from a phenolic condensation product. This material is easily molded, or cast inthe peculiar shapes adapted for phonograph parts and possesses unusual tonal qualities. When solidied it forms a hard, smooth surface which resonantlv conveys the reproduced waves without a,ii"ecting'their purity by add ing metallic and woody sounds such as accompany iihe efforts ot the talking machines now in use.

We claim 1. In a tone arm, an entrance passage which divides and forms separated. diverging passages, separated substantially parallel passages which unite in a common enit ing the interior of said sound box Wit-h the passages of said tone arm.

In testimony whereof, We have hereunto 10 subscribed our names7 this 6th day of November, 1919.

AUSTIN `W. HOOVER. ROBERT WTNTER, JR. 

